France has been spearheading efforts to impose a no-fly zone over Libya.
The issue is currently being considered by the UN Security Council, with the UK and France calling for an urgent resolution and the US suggesting that further measures are needed, as pro-Gaddafi forces advance towards the rebel-held city of Benghazi.
Mr Gueant, the president’s chief adviser for four years, told French radio station Europe 1 that if the Libyans had such incriminating material about Mr Sarkozy’s campaign funding, instead of “saying it all the time, they should just go ahead and do it”.
But he said that all electoral campaign accounts were audited, and the only financial profit that a campaign could make came from “a cheque with a maximum of 4,600 euros (£4,000, $6,400)”.
Responding to the claim that Libya had evidence of bank transfers, Mr Gueant said: “I don’t see how they could have [such comprising evidence] since no such thing exists.”